[Endopolyploidy and yield in diploid and tetraploid sugar beets : III. Methodological results].

An improved procedure is described for selection for a lower degree of endopolyploidy in leaves of sugar beets by means of scoring chloroplast numbers in spongy parenchyma cells. The higher yield of the tetraploid sugar beets with smaller cells (i.e. with a lower degree of endopolyploidy) in the populations is not a result of an increased heterozygosity of these plants.